Bolt capable of bulging on two sides and preparation method thereof

Abstract

The invention provides a bolt capable of bulging on two sides and a preparation method of the bolt, belongs to the technical field of fastening connecting pieces, and aims to solve the problem that in the prior art, a single-face connecting bolt is prone to loosening due to the fact that only a bulge is formed on one side of the single-face connecting bolt, the bolt capable of bulging on two sides comprises a core rod (1), the core rod (1) is sleeved with a left nut (2), a left nail sleeve (3), a right nail sleeve (7) and a right nut (8), in the process that the distance between the left nut (2) and the right nut (8) is gradually reduced, a left bulge (33) can be formed on the left nail sleeve (3), a right bulge (73) can be formed on the right nail sleeve (7), and the left bulge (33) and the right bulge (73) can clamp and fix a mounting plate (9). Therefore, the fastening pressure on the connecting parts on the two sides of the mounting plate is basically the same, the connection is firmer after long-term use, and the connector is suitable for the connection of areas such as closed cavities and pipelines.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of fastening connectors, in particular to a bolt capable of double-side bulging and a preparation method thereof. BACKGROUND

[0002] Bolt fasteners are widely used in various fields of industry. With the upgrading of equipment, bolt fasteners have undergone iterative upgrades from hexagonal bolts, high-lock bolts, and single-side connecting bolts to better adapt to the needs of equipment and meet the requirements of new equipment for fast installation, easy operation, and complex working conditions.

[0003] The existing bolt is used from double-side to single-side connection to meet the demand for easy operation, and the installer can install on one side. For example, Chinese patent document CN 112303092 A, published on February 2, 2021, discloses a new high-strength single-side connecting bolt. The existing single-side connecting bolt forms a bulge only on the installation side of the installation plate during use, and no bulge is formed on the non-installation side of the installation plate. The fastening pressure on the connection parts on both sides of the installation plate is different, and the bolt is prone to loosening during long-term use. SUMMARY

[0004] To solve the problem of easy loosening caused by the single-side bulging of the single-side connecting bolt in the prior art, the present application provides a bolt capable of double-side bulging and a preparation method thereof. The bolt capable of double-side bulging can form a locking bulge on both sides synchronously, so that the fastening pressure on the connection parts on both sides of the installation plate is basically the same, the connection is more firm during long-term use, and the bolt is suitable for connection in closed cavities, pipelines, and other areas, has the advantages of double-side locking, high installation efficiency, high connection freedom, wide application range of interlayer, etc.

[0005] The technical solution adopted by the embodiments of the present application to solve the technical problems is as follows:

[0006] A bolt capable of double-side bulging, comprising a core rod, a left nut, a left nail sleeve, a right nail sleeve, and a right nut are arranged on the core rod in sequence from left to right; when the bolt capable of double-side bulging penetrates the installation hole of the installation plate, the left nail sleeve and the right nail sleeve can be located on the left and right sides of the installation plate respectively, and during the process of gradually reducing the distance between the left nut and the right nut, a left bulge can be formed on the left nail sleeve, and a right bulge can be formed on the right nail sleeve, and the left bulge and the right bulge can clamp and fix the installation plate.

[0007] A preparation method of the above-mentioned bolt capable of double-side bulging, comprising the following steps:

[0008] Step one, manufacturing core rod, left nut, left nail sleeve, left ring, nail body, right ring, right nail sleeve and right nut;

[0009] Step two, installing left nut, left nail sleeve, left ring, nail body, right ring, right nail sleeve and right nut to core rod.

[0010] The beneficial effect of the embodiment of the present application is that the bolt capable of forming bulges on both sides can form locking bulges on both sides synchronously, so that the fastening pressure on both sides of the connecting part of the mounting plate is basically the same, the long-term use connection is more firm, and the bolt is suitable for connection of closed cavities, pipelines and the like, has the advantages of double-sided locking, high installation efficiency, high connection degree of freedom, wide application range of interlayer and the like. BRIEF DESCRIPTION OF DRAWINGS

[0011] The drawings accompanying the specification of this application form a part thereof, serve to provide further understanding of the present application, and together with the description of the exemplary embodiments of the present application and the explanation thereof serve to explain the present application, and do not constitute an improper limitation on the present application.

[0012] Figure 1 is the overall schematic diagram of the bolt capable of forming bulges on both sides according to the present application.

[0013] Figure 2 is the schematic diagram of the core rod.

[0014] Figure 3 is the schematic diagram of the nail body.

[0015] Figure 4 is the front view schematic diagram of the left nut.

[0016] Figure 5 is the perspective view schematic diagram of the left nut.

[0017] Figure 6 is the front view schematic diagram of the left nail sleeve.

[0018] Figure 7 is the perspective view schematic diagram of the left nail sleeve.

[0019] Figure 8 is the front view schematic diagram of the right nail sleeve.

[0020] Figure 9 is the schematic diagram when the bolt capable of forming bulges on both sides according to the present application penetrates the mounting through hole of the mounting plate.

[0021] Figure 10 is the schematic diagram after forming the left bulge on the left nail sleeve and the right bulge on the right nail sleeve.

[0022] The reference signs are explained as follows:

[0023] 1. Core rod; 2. Left nut; 3. Left nail sleeve; 4. Left ring; 5. Nail body; 6. Right ring; 7. Right nail sleeve; 8. Right nut; 9. Mounting plate;

[0024] 11. Tightening head section; 12. Neck break groove; 13. Left-hand threaded section; 14. Polished shank section; 15. Right-hand threaded section;

[0025] 21. Cross groove; 22. Indentation; 23. Right incisor;

[0026] 31. Left minor diameter segment; 32. Left major diameter segment; 33. Left bulge; 34. Left incisor;

[0027] 51. Left conical section; 52. Constant diameter section; 53. Right conical section;

[0028] 71. Right minor diameter segment; 72. Right major diameter segment; 73. Right bulge;

[0029] 91. Install through holes. Detailed Implementation

[0030] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0031] For ease of understanding and description, the following description of the present invention uses absolute positional relationships. Unless otherwise specified, the directional term "above" indicates... Figure 1 The direction above, the directional word "down" indicates Figure 1 The lower side of the middle, the directional word "left" indicates Figure 1 The left side of the direction, the directional word "right" indicates Figure 1 The right-hand direction in the text, the directional word "front" indicates perpendicular to. Figure 1 The direction of the paper and the direction pointing inwards; the directional word "back" indicates perpendicular to. Figure 1 The orientation of the paper is pointed outwards from the viewpoint of the reader or user. This invention is described from the perspective of the reader or user, but the aforementioned directional terms should not be construed as limiting the scope of protection of this invention. Regarding the material, weight, size, angle, and parameters of the components, those skilled in the art can determine or replace them according to actual needs or a limited number of experiments.

[0032] like Figure 1 , Figure 2 , Figure 9 , Figure 10As shown, the bolt capable of double-sided bulging of the embodiment comprises a core rod 1, which is sleeved with a left nut 2, a left nail sleeve 3, a right nail sleeve 7 and a right nut 8, which are sequentially arranged from left to right. The left nut 2 and the left nail sleeve 3 are connected left and right, and the right nail sleeve 7 and the right nut 8 are connected left and right. When the bolt capable of double-sided bulging penetrates the mounting through hole 91 of the mounting plate 9, the left nail sleeve 3 and the right nail sleeve 7 can be located on the left and right sides of the mounting plate 9 respectively. In the process of gradually reducing the distance between the left nut 2 and the right nut 8, a left bulge 33 can be formed on the left nail sleeve 3, and a right bulge 73 can be formed on the right nail sleeve 7. The left bulge 33 and the right bulge 73 can clamp and fix the mounting plate 9.

[0033] The bolt capable of double-sided bulging can form locking bulges (left bulge 33 and right bulge 73) on both sides synchronously, so that the fastening pressure on both sides of the mounting plate 9 is basically the same, the connection is more firm during long-term use, and it is suitable for connection in areas such as closed cavities and pipelines, and has the advantages of double-sided locking, high installation efficiency, high connection degree of freedom, wide application range of interlayer, etc.

[0034] As shown in Figure 1 , Figure 2 , the core rod 1 extends along the left-right direction. The outer peripheral surface of the core rod 1 contains a wrench head section 11, a neck-breaking groove 12, a left-hand thread section 13, a smooth rod section 14 and a right-hand thread section 15, which are sequentially arranged from left to right. The threads on the left-hand thread section 13 are left-hand threads (external threads), and the threads on the right-hand thread section 15 are right-hand threads (external threads). The cross section of the wrench head section 11 can be rectangular or racetrack-shaped. The cross-sectional area of the neck-breaking groove 12 is smaller than the cross-sectional areas of the wrench head section 11 and the left-hand thread section 13.

[0035] The left nut 2 and the left nail sleeve 3 are both sleeved on the left-hand thread section 13. The left nut 2 is threadedly connected with the left-hand thread section 13. The right nail sleeve 7 and the right nut 8 are both sleeved on the right-hand thread section 15. The right nut 8 is threadedly connected with the right-hand thread section 15. The smooth rod section 14 is sleeved with a nail body 5. The nail body 5 is in clearance fit with the smooth rod section 14. The left nut 2, the left nail sleeve 3, the nail body 5, the right nail sleeve 7 and the right nut 8 are sequentially arranged from left to right. When the bolt capable of double-sided bulging penetrates the mounting through hole 91 of the mounting plate 9, the nail body 5 can be sleeved in the mounting through hole 91, and the nail body 5 is in clearance fit with the mounting through hole 91.

[0036] As shown in Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 , Figure 6 , Figure 7As shown, the inner circumferential surface of the left nail sleeve 3 contains a left small-diameter section 31 and a left large-diameter section 32 arranged left and right, the inner diameter of the left small-diameter section 31 is smaller than that of the left large-diameter section 32, the left small-diameter section 31 is in clearance fit with the left-hand thread section 13, and the left large-diameter section 32 has the left ring 4 fitted therein in a matching manner, the left ring 4 is fitted outside the left-hand thread section 13, and the left ring 4 is in clearance fit with both the left large-diameter section 32 and the left-hand thread section 13. The inner circumferential surface of the right nail sleeve 7 contains a right small-diameter section 71 and a right large-diameter section 72 arranged right and left, the inner diameter of the right small-diameter section 71 is smaller than that of the right large-diameter section 72, the right small-diameter section 71 is in clearance fit with the right-hand thread section 15, and the right large-diameter section 72 has the right ring 6 fitted therein in a matching manner, the right ring 6 is fitted outside the right-hand thread section 15, and the right ring 6 is in clearance fit with both the right large-diameter section 72 and the right-hand thread section 15.

[0037] As the distance between the left nut 2 and the right nut 8 gradually decreases, the left nut 2 extrudes the left nail sleeve 3 to the right, the right nut 8 extrudes the right nail sleeve 7 to the left, and the distance between the center of gravity of the left nail sleeve 3 and that of the right nail sleeve 7 gradually decreases, the left nail sleeve 3 can be extruded and deformed to form a left bulge 33, and the right nail sleeve 7 can be extruded and deformed to form a right bulge 73.

[0038] As shown in Figure 1 , Figure 3 , the outer circumferential surface of the nail body 5 contains a left tapered section 51, a constant-diameter section 52, and a right tapered section 53 arranged in sequence from left to right, the left end of the left tapered section 51 abuts against the left ring 4, the right end of the right tapered section 53 abuts against the right ring 6, the left tapered section 51 and the right tapered section 53 are left-right symmetrical and mirror images of each other, and the left ring 4 and the right ring 6 are left-right symmetrical and mirror images of each other.

[0039] The left end surface of the left nail sleeve 3 is provided with left teeth 34, a plurality of left teeth 34 are arranged in interval along the circumference of the left nail sleeve 3, the right end surface of the left nut 2 is provided with right teeth 23, a plurality of right teeth 23 are arranged in interval along the circumference of the left nut 2, and the plurality of left teeth 34 are in meshing connection with the plurality of right teeth 23. The left nail sleeve 3 and the left nut 2 can keep synchronous rotation or stillness, and the outer diameter of the left nail sleeve 3 is the same as that of the left nut 2.

[0040] The left end surface of the left nut 2 is provided with a cross groove 21, the cross groove 21 is composed of four grooves, the four grooves are arranged in uniform interval along the circumference of the left nut 2, and the outer circumferential surface of the left nut 2 is provided with a plurality (such as three) of press recesses 22, the plurality of press recesses 22 are arranged in uniform interval along the circumference of the left nut 2.

[0041] As shown in Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 , Figure 6 , Figure 7 , Figure 8As shown, the left-hand thread section 13 and the right-hand thread section 15 are left-right symmetrical and mirror images of each other, the left nut 2 and the right nut 8 are left-right symmetrical and mirror images of each other, and the left nail sleeve 3 and the right nail sleeve 7 are left-right symmetrical and mirror images of each other.

[0042] A method for manufacturing the bolt capable of bulging on both sides is described below, which comprises the following steps:

[0043] Step one, manufacturing the core rod 1, the left nut 2, the left nail sleeve 3, the left ring 4, the nail body 5, the right ring 6, the right nail sleeve 7, and the right nut 8.

[0044] Step two, installing the left nut 2, the left nail sleeve 3, the left ring 4, the nail body 5, the right ring 6, the right nail sleeve 7, and the right nut 8 on the core rod 1, as shown. Figure 1

[0045] In step one, the manufacturing method of the core rod 1 comprises turning, heat treatment, and external thread rolling, and the specific process is as follows:

[0046] The prepared core rod 1 is characterized by having a wrench head section 11 at one end, and a neck break groove 12 at the right end of the wrench head section 11; a left-hand thread section 13 and a right-hand thread section 15 are machined on the core rod 1; and a smooth rod section 14 is between the left-hand thread section 13 and the right-hand thread section 15.

[0047] In step two, the manufacturing method of the left nut 2 and the right nut 8 comprises drilling, laser tooth cutting, internal thread tapping, and indentation, and the specific process is as follows:

[0048] The prepared nut is characterized by having a cross groove 21 at one end for installing a gun, preventing the nut from rotating with the core rod 1 at the beginning of driving, and having tooth cutting at the other end for matching the tooth shape of the lower end surface of the nail sleeve and driving the nail sleeve to deform; the inner surface of the nail sleeve has a thread pair matched with the core rod for displacement along the core rod; and the three-point indentation 22 of the nut can better prevent loosening.

[0049] In step two, the manufacturing method of the left nail sleeve 3 and the right nail sleeve 7 comprises turning and laser tooth cutting, and the specific process is as follows:

[0050] The prepared nail sleeve is characterized by having a stepped hole at one end for accommodating the ring, and having tooth cutting on one end surface for complete matching with the tooth cutting of the nut, and can be deformed into a bulge to clamp the mounting plate during driving.

[0051] In step two, the manufacturing method of the left ring 4 and the right ring 6 comprises turning, and the specific process is as follows: the prepared ring is characterized by being a hollow circular ring placed in the stepped hole of the nail sleeve, and plays a role in uniformly transmitting deformation force during deformation of the nail sleeve, so that the deformation of the nail sleeve is more uniform.

[0052] ​In step two, the specific process is: the left ring 4 is put into the left large diameter section 32 of the left nail sleeve 3, and the right ring 6 is put into the right large diameter section 72 of the right nail sleeve 7. The left ring 4 and the left nail sleeve 3 are sleeved on the left-hand thread section 13, and the right ring 6 and the right nail sleeve 7 are sleeved on the right-hand thread section 15. The left nut 2 is screwed on the left-hand thread section 13, and the right nut 8 is screwed on the right-hand thread section 15. After the left nut 2 is tightened, the toothed end face at the right end of the left nut 2 is connected with the toothed end face at the left end of the left nail sleeve 3. After the right nut 8 is tightened, the toothed end face at the left end of the right nut 8 is connected with the toothed end face at the right end of the right nail sleeve 7.

[0053] The use method of the bolt capable of double-sided bulging will be introduced below.

[0054] 1. Installation preparation: the bolt capable of double-sided bulging is matched with the installation gun, specifically, the pulling head section 11 is aligned with the installation gun and is loaded into the installation gun, the installation gun is matched with the cross groove 21 at the left end of the left nut 2 to prevent the parts from rotating integrally when the installation is started, the installation gun plays a pressing role on the cross groove 21 at the left end of the left nut 2, and the installation gun plays a rotating role on the core rod 1; the bolt capable of double-sided bulging is placed into the installation through hole 91 of the installation plate 9 by using the installation gun, the left nail sleeve 3 and the right nail sleeve 7 are respectively located on the left side and the right side of the installation plate 9, and the left nut 2 and the right nut 8 are also respectively located on the left side and the right side of the installation plate 9, as shown in Figure 1 .

[0055] 2. Riveting deformation: the installation gun is started to rotate with the core rod 1, the torque transmitted by the core rod 1 to the left nut 2 overcomes the pressing force of the installation gun on the left nut 2, the left nut 2 and the right nut 8 move towards the installation plate 9 under the driving of the threads of the core rod 1, the distance between the left nut 2 and the right nut 8 gradually decreases, the toothed transmission torque of the left nut 2 is transmitted to the toothed transmission torque of the left nail sleeve 3, and the toothed transmission torque of the right nut 8 is transmitted to the toothed transmission torque of the right nail sleeve 7, the left nail sleeve 3 and the right nail sleeve 7 rotate accordingly, the distance between the left nail sleeve 3 and the right nail sleeve 7 gradually decreases along with the gradual decrease of the distance between the left nut 2 and the right nut 8, the middle part and the right part of the left nail sleeve 3 are deformed to form the left bulge 33 under the extrusion of the left nut 2 and the installation plate 9, and the middle part and the left part of the right nail sleeve 7 are deformed to form the right bulge 73 under the extrusion of the right nut 8 and the installation plate 9, as shown in Figure 2 .

[0056] Installation completion: after the head (the left bulge 33 and the right bulge 73) is completely formed, the deformation resistance of the nail sleeve is greater than the breaking torque of the core rod 1 at the neck breaking groove 12, the core rod 1 is broken from the neck breaking groove 12, the installation is completed, and the double-sided bulges (the left bulge 33 and the right bulge 73) are formed on the left side and the right side of the installation plate 9.

[0057] The specific preparation and application of the bolt capable of double-sided bulging will be introduced below.

[0058] Example 1

[0059] Part preparation: Ti662 (TC10) titanium alloy core rod 1, Ti6Al4V (TC4) titanium alloy nut (left nut 2 and right nut 8), 0Cr18Ni9Ti (304) stainless steel sleeve (left sleeve 3 and right sleeve 7), polyformal ring (left ring 4 and right ring 6).

[0060] Assembly: Put the polyformal ring into the stepped hole inside the 0Cr18Ni9Ti (304) stainless steel sleeve; Put the sleeve with the ring from both sides on the upper and lower ends of the Ti662 (TC10) titanium alloy core rod, the end surface of the sleeve with the stepped hole faces the middle polished rod direction of the core rod, and the end surface of the sleeve with the teeth faces the two ends of the core rod; Screw the Ti6Al4V (TC4) left-handed nut from the core rod wrench head and the Ti6Al4V (TC4) right-handed nut from the other end of the core rod, respectively, the end surface of the nut with the teeth faces the polished rod direction of the core rod, the end surface of the nut with the cross slot faces the two ends of the core rod, the thread direction of the nut is consistent with that of the core rod, and the tooth end surface of the nut after tightening should cooperate with the tooth end surface of the sleeve, to obtain the assembled bolt (the bolt capable of bulging on both sides).

[0061] Installation: Install the gun and the cross-tooth slot at the rear end of the left-handed nut in position, start the gun to rotate with the core rod, the screw thread of the core rod drives the nut to displace, the teeth of the nut transmit torque to the teeth of the sleeve, driving the sleeve to rotate integrally, the sleeve is extruded and deformed under the installation plate, forming double-side bulging bulges, the core rod is broken from the broken neck groove, and the installation is completed, forming bulges (left bulge 33 and right bulge 73) on both sides of the installation plate.

[0062] Example 2

[0063] Part preparation: GH4169 high-temperature alloy core rod 1, GH4169 high-temperature alloy nut (left nut 2 and right nut 8), 0Cr18Ni9Ti (304) stainless steel sleeve (left sleeve 3 and right sleeve 7), polyformal ring (left ring 4 and right ring 6).

[0064] Assembly and installation are consistent with example 2.

[0065] Application example 3

[0066] Part preparation: GH2132 high-temperature alloy core rod 1, 45 carbon steel nut (left nut 2 and right nut 8), 5056 aluminum alloy sleeve (left sleeve 3 and right sleeve 7), polyformal ring (left ring 4 and right ring 6).

[0067] Assembly and installation are consistent with example 1.

[0068] Application example 4

[0069] Part preparation: Ti3Al8V6Cr4Zr4Mo (TB9) titanium alloy core rod 1, Ti6Al4V (TC4) titanium alloy nut (left nut 2 and right nut 8), CP-Ti (TA1) titanium alloy nail sleeve (left nail sleeve 3 and right nail sleeve 7), polyformaldehyde ring (left ring 4 and right ring 6).

[0070] Assembly and installation are consistent with example 1.

[0071] The above is only a specific embodiment of the present application, which cannot limit the scope of the application. Therefore, the replacement of equivalent components or equivalent changes and modifications made within the scope of the present application should still belong to the scope of the present application. In addition, the technical features in the present application can be freely combined with each other, and the technical features can be freely combined with each other.

Claims

1. A bolt capable of bulging on both sides, characterized in that, The bolt capable of double-sided bulging includes a core rod (1), which is fitted with a left nut (2), a left nail sleeve (3), a right nail sleeve (7), and a right nut (8). The left nut (2), left nail sleeve (3), right nail sleeve (7), and right nut (8) are arranged sequentially from left to right. When the bolt capable of double-sided bulging is inserted into the mounting through hole (91) of the mounting plate (9), the left nail sleeve (3) and the right nail sleeve (7) can be located on the left and right sides of the mounting plate (9), respectively. As the distance between the left nut (2) and the right nut (8) gradually decreases, a left bulge (33) can be formed on the left nail sleeve (3), and a right bulge (73) can be formed on the right nail sleeve (7). The left bulge (33) and the right bulge (73) can clamp and fix the mounting plate (9).

2. The bolt capable of double-sided bulging according to claim 1, characterized in that, The core rod (1) extends in the left and right direction. The outer circumference of the core rod (1) contains a wrench head section (11), a neck groove (12), a left-hand threaded section (13), a smooth rod section (14), and a right-hand threaded section (15) arranged from left to right. The thread on the left-hand threaded section (13) is a left-hand thread, and the thread on the right-hand threaded section (15) is a right-hand thread.

3. The bolt capable of double-sided bulging according to claim 2, characterized in that, The left nut (2) and the left nail sleeve (3) are both fitted outside the left-hand threaded section (13). The left nut (2) is threadedly connected to the left-hand threaded section (13). The right nail sleeve (7) and the right nut (8) are both fitted outside the right-hand threaded section (15). The right nut (8) is threadedly connected to the right-hand threaded section (15). The smooth rod section (14) is fitted with a nail body (5). When the bolt that can bulge on both sides is inserted into the mounting through hole (91) of the mounting plate (9), the nail body (5) can be fitted inside the mounting through hole (91).

4. The bolt capable of double-sided bulging according to claim 3, characterized in that, The inner circumferential surface of the left nail sleeve (3) contains a left minor diameter section (31) and a left major diameter section (32) arranged on the left and right respectively. The inner diameter of the left minor diameter section (31) is smaller than the inner diameter of the left major diameter section (32). The left minor diameter section (31) is clearance-fitted with the left-hand threaded section (13). A left ring (4) is fitted inside the left major diameter section (32). The left ring (4) is fitted outside the left-hand threaded section (13). The inner circumferential surface of the right nail sleeve (7) contains a right minor diameter section (71) and a right major diameter section (72) arranged on the left and right respectively. The inner diameter of the right minor diameter section (71) is smaller than the inner diameter of the right major diameter section (72). The right minor diameter section (71) is clearance-fitted with the right-hand threaded section (15). A right ring (6) is fitted inside the right major diameter section (72). The right ring (6) is fitted outside the right-hand threaded section (15).

5. The bolt capable of double-sided bulging according to claim 4, characterized in that, As the distance between the left nut (2) and the right nut (8) gradually decreases, the distance between the center of gravity of the left nail sleeve (3) and the center of gravity of the right nail sleeve (7) also gradually decreases.

6. The bolt capable of double-sided bulging according to claim 4, characterized in that, The outer circumferential surface of the nail body (5) contains a left conical section (51), a constant diameter section (52), and a right conical section (53) arranged sequentially from left to right. The left end of the left conical section (51) abuts against the left ring (4), and the right end of the right conical section (53) abuts against the right ring (6). The left ring (4) and the right ring (6) are symmetrical and mirror images of each other. The left conical section (51) and the right conical section (53) are symmetrical and mirror images of each other.

7. The bolt capable of double-sided bulging according to claim 1, characterized in that, The left end face of the left nail sleeve (3) is provided with a left cutting tooth (34), and the right end face of the left nut (2) is provided with a right cutting tooth (23). The left cutting tooth (34) and the right cutting tooth (23) are engaged and connected.

8. The bolt capable of double-sided bulging according to claim 1, characterized in that, The left end face of the left nut (2) is provided with a cross groove (21), and the outer circumferential surface of the left nut (2) is provided with multiple indentations (22), which are evenly spaced along the circumference of the left nut (2).

9. The bolt capable of double-sided bulging according to claim 2, characterized in that, The left-hand thread segment (13) and the right-hand thread segment (15) are symmetrical and mirror images of each other. The left nut (2) and the right nut (8) are symmetrical and mirror images of each other. The left pin sleeve (3) and the right pin sleeve (7) are symmetrical and mirror images of each other.

10. A method for preparing a bolt capable of double-sided bulging as described in claim 4, characterized in that, The method for preparing the bolt capable of double-sided bulging includes the following steps: Step 1: Manufacture the core rod (1), left nut (2), left nail sleeve (3), left ring (4), nail body (5), right ring (6), right nail sleeve (7) and right nut (8); Step 2: Install the left nut (2), left nail sleeve (3), left ring (4), nail body (5), right ring (6), right nail sleeve (7) and right nut (8) onto the core rod (1).

Images